code: def test_compiling_core_header(self):
      code = r"""
          extern "C" __global__ void _test_ker_() { }
          """
      code = self.header + code
      options = () if self.cxx is None else (self.cxx,)
      ker = cupy.RawKernel(
          code, "_test_ker_", options=options, backend="nvrtc"
      )
      ker((1,), (1,), ())
      cupy.cuda.Device().synchronize()
  
imports: import unittest
  import sys
  import numpy
  import pytest
  import cupy
  from cupy._core import core
  from cupy import testing
  from cupy_tests.core_tests import test_raw
label_desc: Use image node_id 3 for calling the TestCuPyHeaders obj's underlying member method code with example usage: obj.test_compiling_core_header() without return types